Diagnosing Moyamoya disease

Persons with moyamoya disease may have sensory and cognitive impairments, involuntary movements, vision problems and speech deficits. Speech deficiencies usually fall into the category of aphasia, or an impaired ability to speak and understand others.

Cerebral angiography – an X-ray study of the blood vessels using a dye – is the principal form of imaging used for the diagnosis of moyamoya disease. The characteristic findings of moyamoya disease on an angiogram are traditionally described in stages, which progress from early narrowing of the carotid arteries to the formation of moyamoya vessels and then to the disappearance of these vessels with maintenance of blood flow by the external carotid and vertebral arterial systems.

Noninvasive imaging techniques also may be used in the diagnosis of moyamoya disease. When magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) demonstrate blockage of carotid arteries and moyamoya vessels on both sides, a cerebral angiogram is not needed for a diagnosis. Moyamoya MRI scans show the brain's enlarged, extra blood vessels by using magnetic fields and radio waves to create a detailed picture of the brain tissues. MRI scans can reveal whether the patient has ever had a stroke or TIA "mini-stroke," one of the clearest symptoms of Moyamoya disease.

This MRI scan was obtained as part of a research study looking at blood vessel walls in moyamoya. The scan shows the spinal fluid as white. The spinal fluid surrounds the blood vessels at the base of the brain where the narrowing generally occurs. In this patient, the main artery (the carotid artery) on the right of the image is normal (white arrow). The arteries on the left are abnormally small (white arrow head). These pictures show that the narrowing is not from a buildup of material in the wall of the artery, as occurs with artherosclerotic disease and cholesterol plaque.

Once the diagnosis is confirmed, other imaging techniques may be used to measure blood flow and other aspects of the recovery and disease. Washington University neuroradiologists are experts in diagnosing and following moyamoya disease. Colin Derdeyn, MD, co-director of the Moyamoya Center at Washington University, uses positron emission tomography (PET) in an NINDS*-sponsored clinical trial to study blood flow to the brain and oxygen use in patients with moyamoya.

The stages of moyamoya are described in the six-stage classification of Suzuki: